WHAT A RELIEF: Jenrry Mejia, joking with manager Jerry Manuel, pitched three shutout innings in relief during yesterday’s 11-2 win over the Marlins. The 20-year old could be a setup man for Frankie Rodriguez. Reuters Photo: REUTERS

JUPITER, Fla. — Jerry Manuel might have to trade in his windbreaker for a straitjacket before spring training concludes.

A few more dominant performances from rookie Jenrry Mejia will have the Mets manager speaking in tongues, at a previously unattained octave level.

Of course, that doesn’t address the issue of where Mejia is better suited: in the Mets’ bullpen or back in the minor leagues continuing to hone his starting skills.

But after watching the 20-year-old righty fire three shutout innings of relief yesterday in the Mets’ 11-2 exhibition victory over the Marlins, the manager struck a familiar chord.

“[Mejia] wears No. 76 and Frankie is No. 75, if you know what I mean,” Manuel said, referring to the uniform numbers worn by Mejia and closer Francisco Rodriguez. “They might follow each other out there. That’s what I’m trying to tell you.”

With no slam-dunk option for the setup role and Mejia’s stock on the rise, Manuel certainly can dream about employing a tandem of Mejia-Rodriguez in the late innings. Nevertheless, Manuel may have to convince team brass the rookie is ready for the majors and suited for relief.

“Let’s wait until we get to the end of spring training before we get to that point,” GM Omar Minaya said.

But Minaya made it known before yesterday’s game that the plan is for Mejia to begin the season as a starter for Double-A Binghamton.

In six innings this spring, Mejia has not allowed a run. Manuel summoned the rookie in the fifth inning yesterday in part because he wanted to see how Mejia fared against the Marlins’ best hitters, Hanley Ramirez and Dan Uggla.

Mejia retired Ramirez to end the fifth before getting Uggla to start the sixth. It came on a day John Maine made his spring debut by allowing one run on two hits and a walk over 12⁄3 innings. Maine exited after throwing 39 pitches, one less than his prescribed limit.

R.A. Dickey pitched 21⁄3 shutout innings before Mejia got the ball and unleashed his cutter on the Marlins.

“I [prefer] starting, but I feel pretty good about relief,” Mejia said.

Does Manuel anticipate having to battle the front office over where Mejia begins the season?

“I think they can see a few things,” Manuel said. “We keep talking about it. They can see some things.”

The manager insists his plan would be to ease Mejia into the setup role.

Ryota Igarashi and Bobby Parnell are among the options to pitch the eighth inning at the season’s start.

As the spring progresses, the Mets will have to decide whether to stretch out Mejia to prepare him for a starting assignment in the minors or if his appearances should be condensed to one or two innings, readying him for the bullpen.

But he’s already got his teammates’ attention.

“He throws strikes,” catcher Rod Barajas said. “I see a lot of guys who try to nibble, they don’t trust their stuff. He goes out there and throws strikes. Here it is, try and hit it.”

Barajas, an 11-year veteran, was asked how Mejia compares among young pitchers he’s caught.

“I’ve caught some guys with special arms, but this is probably age-wise the best stuff I’ve seen,” Barajas said.

“It’s hard to hit a straight fastball in the mid-90s. Imagine the ball moving. It makes it even harder.”